Government Assistance, Non-freight Accounts Receivable

No definition available.

Name:	csx_GovernmentAssistanceNonFreightAccountsReceivable
Namespace Prefix:	csx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Increase (Decrease) In Depreciation Expense

+ References

No definition available.

+ Details

Name:	csx_IncreaseDecreaseInDepreciationExpense
Namespace Prefix:	csx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of total gross assets depreciated under the group-life method of accounting. Does not include other assets which are depreciated on a straight line basis.

+ References

No definition available.

+ Details

Name:	csx_PercentageOfAssetsDepreciatedUnderGroupLifeMethod
Namespace Prefix:	csx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of labor costs relating to the deconstruction of old track based upon an analysis of track replacement process.

+ References

No definition available.

+ Details

Name:	csx_PercentageOfLaborCostRailInstallationDeconstructionOfOldTrack
Namespace Prefix:	csx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of labor costs relating to the installation of new track based upon an analysis of track replacement process.

+ References

No definition available.

+ Details

Name:	csx_PercentageOfLaborCostRailInstallationInstallationOfNewTrack
Namespace Prefix:	csx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The frequency with which life studies are required, by Surface Transportation Board (STB) to be performed.

+ References

No definition available.

+ Details

Name:	csx_PropertyPlantAndEquipmentLifeStudiesFrequencyPeriod
Namespace Prefix:	csx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 942
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480095/942-10-S50-1

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 942
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480035/942-10-S99-6

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482130/360-10-45-4

+ Details

Name:	us-gaap_AssetImpairmentCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of gain (loss) on sale or disposal of property, plant and equipment assets, excluding oil and gas property and timber property.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482130/360-10-45-5

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482099/360-10-50-3

+ Details

Name:	us-gaap_GainLossOnDispositionOfAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of increase in asset from government assistance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 832
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483507/832-10-50-3

+ Details

Name:	us-gaap_GovernmentAssistanceAssetIncrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Indicates line item in statement of financial position that includes increase in asset from government assistance.

+ References

+ Details

Name:	us-gaap_GovernmentAssistanceAssetIncreaseStatementOfFinancialPositionExtensibleEnumeration
Namespace Prefix:	us-gaap_
Data Type:	enum2:enumerationSetItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(8))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(13))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482099/360-10-50-1

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 7A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-7A

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=csx_TotalEquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ChangeInAccountingEstimateByTypeAxis=csx_ServiceLifeSalvageValueAndOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=srt_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=csx_RoadTotalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Properties - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
Properties - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2026	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Percentage of labor costs relating to the deconstruction of old track		20.00%
Percentage of labor costs relating to the installation of new track		80.00%
Percentage of assets depreciated under the group-life method		86.00%
Properties		$ 53,816	$ 52,191
Gains on sale of properties		17	11	$ 34
Impairment expense		$ 26	$ 24	2
Government Assistance, Asset, Increase, Statement of Financial Position [Extensible Enumeration]		Properties	Properties
Government assistance, asset, increase		$ 216	$ 246	$ 84
Non-freight accounts receivable		121	39
Equipment assets
Property, Plant and Equipment [Line Items]
Properties		$ 11,264	11,162
Life studies, frequency period		3 years
Equipment assets \| Service Life, Salvage Value And Other \| Forecast
Property, Plant and Equipment [Line Items]
Expected decrease in depreciation expense	$ 40
Road and track assets
Property, Plant and Equipment [Line Items]
Properties		$ 39,268	$ 37,684
Life studies, frequency period		6 years